Film capacitor

Abstract

A film capacitor including a first dielectric film, a second dielectric film, a first internal electrode, a second internal electrode, a first external electrode, and a second external electrode. The first internal electrode includes a first connection portion, a first main electrode portion contiguous with the first connection portion and thinner than the first connection portion, and a first thin film portion extending from the first main electrode portion and thinner than the first main electrode portion. The second internal electrode includes a second connection portion and a second main electrode portion contiguous with the second connection portion and thinner than the second connection portion. The first main electrode portion opposes the second main electrode portion with the first dielectric film interposed therebetween and does not oppose the second connection portion, and the first thin film portion opposes the second connection portion with the first dielectric film interposed therebetween.

The invention claimed is: 
     
       1. A film capacitor comprising:
 a stacked body including:
 a first dielectric film having a first surface and a second surface opposite to the first surface; 
 a second dielectric film having a first surface and a second surface opposite to the first surface, the second dielectric film being arranged such that the first surface of the second dielectric film opposes the second surface of the first dielectric film; 
 a first internal electrode on the first surface of the first dielectric film, the first internal electrode including a first connection portion, a first main electrode portion contiguous with the first connection portion and thinner than the first connection portion, and a first thin film portion extending from the first main electrode portion and thinner than the first main electrode portion; and 
 a second internal electrode between the first dielectric film and the second dielectric film, the second internal electrode including a second connection portion, and a second main electrode portion contiguous with the second connection portion and thinner than the second connection portion, wherein 
 the first main electrode portion opposes the second main electrode portion with the first dielectric film interposed therebetween, and does not oppose the second connection portion, and 
 the first thin film portion opposes the second connection portion with the first dielectric film interposed therebetween; 
 
 a first external electrode on a first end surface of the stacked body and electrically connected to the first connection portion of the first internal electrode and separated from the second internal electrode; and 
 a second external electrode on a second end surface of the stack body opposite the first end surface and electrically connected to the second connection portion of the second internal electrode and separated from the first internal electrode, 
 wherein, in a direction from the first external electrode to the second external electrode, a length of the first thin film portion is 50,000 times or more a difference between a maximum thickness of the first main electrode portion and a maximum thickness of the first thin film portion. 
 
     
     
       2. The film capacitor according to  claim 1 , wherein the second internal electrode is on the first surface of the second dielectric film. 
     
     
       3. The film capacitor according to  claim 1 , wherein the second internal electrode is on the second surface of the first dielectric film. 
     
     
       4. The film capacitor according to  claim 1 , wherein
 the second internal electrode further includes a second thin film portion extending from the second main electrode portion and is thinner than the second main electrode portion, the second main electrode portion does not oppose the first connection portion with the first dielectric film interposed therebetween, and 
 the second thin film portion opposes the first connection portion with the first dielectric film interposed therebetween. 
 
     
     
       5. The film capacitor according to  claim 1 , wherein the maximum thickness of the first thin film portion is smaller than a difference between a maximum thickness of the first connection portion and the maximum thickness of the first main electrode portion. 
     
     
       6. The film capacitor according to  claim 1 , wherein the maximum thickness of the first thin film portion is 7 nm or less. 
     
     
       7. The film capacitor according to  claim 1 , wherein the first thin film portion opposes both the second main electrode portion and the second connection portion. 
     
     
       8. The film capacitor according to  claim 7 , wherein, in the direction from the first external electrode toward the second external electrode, the first thin film portion is shorter than the first main electrode portion, and a first region of the first thin film portion opposing the second main electrode portion is longer than a second region of the first thin film portion opposing the second connection portion. 
     
     
       9. The film capacitor according to  claim 8 , wherein, in the direction from the first external electrode toward the second external electrode, a length of the first region of the first thin film portion opposing the second main electrode portion is 4 mm or less. 
     
     
       10. The film capacitor according to  claim 1 , wherein the second connection portion is made of a material having a lower electrical conductivity than the first thin film portion. 
     
     
       11. The film capacitor according to  claim 1 , wherein
 the second internal electrode is provided on the first surface of the second dielectric film, and 
 the second connection portion is made of a material having a lower electrical conductivity on a side opposing the first thin film portion with the first dielectric film interposed therebetween than on a side opposing the second dielectric film. 
 
     
     
       12. The film capacitor according to  claim 10 , wherein
 the second connection portion is made of a material containing zinc as a main component thereof, and 
 the first thin film portion is made of a material containing aluminum as a main component thereof. 
 
     
     
       13. The film capacitor according to  claim 1 , wherein
 the first dielectric film contains a curable resin as a main component thereof, and 
 the second dielectric film contains a curable resin as a main component thereof. 
 
     
     
       14. A film capacitor comprising:
 a stacked body including:
 a first dielectric film having a first surface and a second surface opposite to the first surface; 
 a second dielectric film having a first surface and a second surface opposite to the first surface, the second dielectric film being arranged such that the first surface of the second dielectric film opposes the second surface of the first dielectric film; 
 a first internal electrode on the first surface of the first dielectric film, the first internal electrode including a first main electrode portion, and a first thin film portion extending from the first main electrode portion and thinner than the first main electrode portion; and 
 a second internal electrode between the first dielectric film and the second dielectric film, the second internal electrode including a first connection portion, a second main electrode portion contiguous with the first connection portion and thinner than the first connection portion, a second connection portion, and a third main electrode portion separated from the second main electrode portion and contiguous with the second connection portion and thinner than the second connection portion, wherein 
 the first main electrode portion opposes the second main electrode portion and the third main electrode portion with the first dielectric film interposed therebetween, and does not oppose the second connection portion, and 
 the first thin film portion opposes the second connection portion with the first dielectric film interposed therebetween; 
 
 a first external electrode on a first end surface of the stacked body and electrically connected to the first connection portion of the second internal electrode and separated from the first internal electrode; and 
 a second external electrode on a second end surface of the stack body opposite the first end surface and electrically connected to the second connection portion of the second internal electrode and separated from the first internal electrode, 
 wherein, in a direction from the first external electrode to the second external electrode, a length of the first thin film portion is 50,000 times or more a difference between a maximum thickness of the first main electrode portion and a maximum thickness of the first thin film portion. 
 
     
     
       15. The film capacitor according to  claim 14 , wherein
 the first internal electrode further includes a second thin film portion extending from the first main electrode portion toward the first external electrode and thinner than the first main electrode portion, the first main electrode portion does not oppose the first connection portion with the first dielectric film interposed therebetween, and 
 the second thin film portion opposes the first connection portion with the first dielectric film interposed therebetween. 
 
     
     
       16. The film capacitor according to  claim 14 , wherein the second internal electrode is on the first surface of the second dielectric film. 
     
     
       17. The film capacitor according to  claim 14 , wherein the second internal electrode is on the second surface of the first dielectric film. 
     
     
       18. The film capacitor according to  claim 14 , wherein the second connection portion is made of a material having a lower electrical conductivity than the first thin film portion. 
     
     
       19. The film capacitor according to  claim 18 , wherein
 the second connection portion is made of a material containing zinc as a main component thereof, and 
 the first thin film portion is made of a material containing aluminum as a main component thereof.